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crypto: arm64/aes-ccm - yield NEON after every block of input
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Avoid excessive scheduling delays under a preemptible kernel by
yielding the NEON after every block of input.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Ard Biesheuvel authored and Herbert Xu committed May 11, 2018
1 parent d82f37a commit 7b67ae4
Showing 1 changed file with 95 additions and 55 deletions.
150 changes: 95 additions & 55 deletions arch/arm64/crypto/aes-ce-ccm-core.S
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Original file line number Diff line number Diff line change
Expand Up @@ -19,24 +19,33 @@
* u32 *macp, u8 const rk[], u32 rounds);
*/
ENTRY(ce_aes_ccm_auth_data)
ldr w8, [x3] /* leftover from prev round? */
frame_push 7

mov x19, x0
mov x20, x1
mov x21, x2
mov x22, x3
mov x23, x4
mov x24, x5

ldr w25, [x22] /* leftover from prev round? */
ld1 {v0.16b}, [x0] /* load mac */
cbz w8, 1f
sub w8, w8, #16
cbz w25, 1f
sub w25, w25, #16
eor v1.16b, v1.16b, v1.16b
0: ldrb w7, [x1], #1 /* get 1 byte of input */
subs w2, w2, #1
add w8, w8, #1
0: ldrb w7, [x20], #1 /* get 1 byte of input */
subs w21, w21, #1
add w25, w25, #1
ins v1.b[0], w7
ext v1.16b, v1.16b, v1.16b, #1 /* rotate in the input bytes */
beq 8f /* out of input? */
cbnz w8, 0b
cbnz w25, 0b
eor v0.16b, v0.16b, v1.16b
1: ld1 {v3.4s}, [x4] /* load first round key */
prfm pldl1strm, [x1]
cmp w5, #12 /* which key size? */
add x6, x4, #16
sub w7, w5, #2 /* modified # of rounds */
1: ld1 {v3.4s}, [x23] /* load first round key */
prfm pldl1strm, [x20]
cmp w24, #12 /* which key size? */
add x6, x23, #16
sub w7, w24, #2 /* modified # of rounds */
bmi 2f
bne 5f
mov v5.16b, v3.16b
Expand All @@ -55,33 +64,43 @@ ENTRY(ce_aes_ccm_auth_data)
ld1 {v5.4s}, [x6], #16 /* load next round key */
bpl 3b
aese v0.16b, v4.16b
subs w2, w2, #16 /* last data? */
subs w21, w21, #16 /* last data? */
eor v0.16b, v0.16b, v5.16b /* final round */
bmi 6f
ld1 {v1.16b}, [x1], #16 /* load next input block */
ld1 {v1.16b}, [x20], #16 /* load next input block */
eor v0.16b, v0.16b, v1.16b /* xor with mac */
bne 1b
6: st1 {v0.16b}, [x0] /* store mac */
beq 6f

if_will_cond_yield_neon
st1 {v0.16b}, [x19] /* store mac */
do_cond_yield_neon
ld1 {v0.16b}, [x19] /* reload mac */
endif_yield_neon

b 1b
6: st1 {v0.16b}, [x19] /* store mac */
beq 10f
adds w2, w2, #16
adds w21, w21, #16
beq 10f
mov w8, w2
7: ldrb w7, [x1], #1
mov w25, w21
7: ldrb w7, [x20], #1
umov w6, v0.b[0]
eor w6, w6, w7
strb w6, [x0], #1
subs w2, w2, #1
strb w6, [x19], #1
subs w21, w21, #1
beq 10f
ext v0.16b, v0.16b, v0.16b, #1 /* rotate out the mac bytes */
b 7b
8: mov w7, w8
add w8, w8, #16
8: mov w7, w25
add w25, w25, #16
9: ext v1.16b, v1.16b, v1.16b, #1
adds w7, w7, #1
bne 9b
eor v0.16b, v0.16b, v1.16b
st1 {v0.16b}, [x0]
10: str w8, [x3]
st1 {v0.16b}, [x19]
10: str w25, [x22]

frame_pop
ret
ENDPROC(ce_aes_ccm_auth_data)

Expand Down Expand Up @@ -126,19 +145,29 @@ ENTRY(ce_aes_ccm_final)
ENDPROC(ce_aes_ccm_final)

.macro aes_ccm_do_crypt,enc
ldr x8, [x6, #8] /* load lower ctr */
ld1 {v0.16b}, [x5] /* load mac */
CPU_LE( rev x8, x8 ) /* keep swabbed ctr in reg */
frame_push 8

mov x19, x0
mov x20, x1
mov x21, x2
mov x22, x3
mov x23, x4
mov x24, x5
mov x25, x6

ldr x26, [x25, #8] /* load lower ctr */
ld1 {v0.16b}, [x24] /* load mac */
CPU_LE( rev x26, x26 ) /* keep swabbed ctr in reg */
0: /* outer loop */
ld1 {v1.8b}, [x6] /* load upper ctr */
prfm pldl1strm, [x1]
add x8, x8, #1
rev x9, x8
cmp w4, #12 /* which key size? */
sub w7, w4, #2 /* get modified # of rounds */
ld1 {v1.8b}, [x25] /* load upper ctr */
prfm pldl1strm, [x20]
add x26, x26, #1
rev x9, x26
cmp w23, #12 /* which key size? */
sub w7, w23, #2 /* get modified # of rounds */
ins v1.d[1], x9 /* no carry in lower ctr */
ld1 {v3.4s}, [x3] /* load first round key */
add x10, x3, #16
ld1 {v3.4s}, [x22] /* load first round key */
add x10, x22, #16
bmi 1f
bne 4f
mov v5.16b, v3.16b
Expand All @@ -165,9 +194,9 @@ CPU_LE( rev x8, x8 ) /* keep swabbed ctr in reg */
bpl 2b
aese v0.16b, v4.16b
aese v1.16b, v4.16b
subs w2, w2, #16
bmi 6f /* partial block? */
ld1 {v2.16b}, [x1], #16 /* load next input block */
subs w21, w21, #16
bmi 7f /* partial block? */
ld1 {v2.16b}, [x20], #16 /* load next input block */
.if \enc == 1
eor v2.16b, v2.16b, v5.16b /* final round enc+mac */
eor v1.16b, v1.16b, v2.16b /* xor with crypted ctr */
Expand All @@ -176,18 +205,29 @@ CPU_LE( rev x8, x8 ) /* keep swabbed ctr in reg */
eor v1.16b, v2.16b, v5.16b /* final round enc */
.endif
eor v0.16b, v0.16b, v2.16b /* xor mac with pt ^ rk[last] */
st1 {v1.16b}, [x0], #16 /* write output block */
bne 0b
CPU_LE( rev x8, x8 )
st1 {v0.16b}, [x5] /* store mac */
str x8, [x6, #8] /* store lsb end of ctr (BE) */
5: ret

6: eor v0.16b, v0.16b, v5.16b /* final round mac */
st1 {v1.16b}, [x19], #16 /* write output block */
beq 5f

if_will_cond_yield_neon
st1 {v0.16b}, [x24] /* store mac */
do_cond_yield_neon
ld1 {v0.16b}, [x24] /* reload mac */
endif_yield_neon

b 0b
5:
CPU_LE( rev x26, x26 )
st1 {v0.16b}, [x24] /* store mac */
str x26, [x25, #8] /* store lsb end of ctr (BE) */

6: frame_pop
ret

7: eor v0.16b, v0.16b, v5.16b /* final round mac */
eor v1.16b, v1.16b, v5.16b /* final round enc */
st1 {v0.16b}, [x5] /* store mac */
add w2, w2, #16 /* process partial tail block */
7: ldrb w9, [x1], #1 /* get 1 byte of input */
st1 {v0.16b}, [x24] /* store mac */
add w21, w21, #16 /* process partial tail block */
8: ldrb w9, [x20], #1 /* get 1 byte of input */
umov w6, v1.b[0] /* get top crypted ctr byte */
umov w7, v0.b[0] /* get top mac byte */
.if \enc == 1
Expand All @@ -197,13 +237,13 @@ CPU_LE( rev x8, x8 )
eor w9, w9, w6
eor w7, w7, w9
.endif
strb w9, [x0], #1 /* store out byte */
strb w7, [x5], #1 /* store mac byte */
subs w2, w2, #1
beq 5b
strb w9, [x19], #1 /* store out byte */
strb w7, [x24], #1 /* store mac byte */
subs w21, w21, #1
beq 6b
ext v0.16b, v0.16b, v0.16b, #1 /* shift out mac byte */
ext v1.16b, v1.16b, v1.16b, #1 /* shift out ctr byte */
b 7b
b 8b
.endm

/*
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